| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical head device capable of surely removing the offset component included in a track error signal. SOLUTION: A photodetector 23 for detecting an off-track signal applied to this optical head device has four photodetecting regions 23a to 23d which detect the off-track signal and are arranged apart from each other. The region irradiated with the light of the high intensity part where all of the zero order diffracted light, first order diffracted light and minus first order diffracted light of the reflected light reflected from an optical disk between these four photodetecting regions is provided with a central photodetecting region consisting of the fifth to eighth photodetecting regions 23e to 23h to remove the offset component included in the off-track signal. As a result, the influence of the offset component included in the off-track signal, i.e., lens shift, on the track error signal is eliminated. |
